US20090320398A1 - Monolithic integrated structural panels especially useful for aircraft structures and methods of making the same - Google Patents

Monolithic integrated structural panels especially useful for aircraft structures and methods of making the same Download PDF

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Publication number
US20090320398A1
US20090320398A1 US12/165,213 US16521308A US2009320398A1 US 20090320398 A1 US20090320398 A1 US 20090320398A1 US 16521308 A US16521308 A US 16521308A US 2009320398 A1 US2009320398 A1 US 2009320398A1
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Prior art keywords
frame
members
fiber
composite material
stringer members
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US12/165,213
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US8079549B2 (en
Inventor
Roberto Paton GOUVEA
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Embraer SA
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Embraer SA
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Priority to US12/165,213 priority Critical patent/US8079549B2/en
Assigned to EMBRAER - EMPRESA BRASILEIRA DE AERONAUTICA S.A. reassignment EMBRAER - EMPRESA BRASILEIRA DE AERONAUTICA S.A. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: GOUVEIA, ROBERTO PATON
Priority to PCT/BR2008/000379 priority patent/WO2010006391A1/en
Priority to BRPI0822480A priority patent/BRPI0822480B1/en
Priority to EP08876562.3A priority patent/EP2307271B1/en
Publication of US20090320398A1 publication Critical patent/US20090320398A1/en
Application granted granted Critical
Publication of US8079549B2 publication Critical patent/US8079549B2/en
Assigned to Embraer S.A. reassignment Embraer S.A. CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: EMBRAER - EMPRESA BRASILEIRA DE AERONAUTICA S.A.
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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64CAEROPLANES; HELICOPTERS
    • B64C1/00Fuselages; Constructional features common to fuselages, wings, stabilising surfaces or the like
    • B64C1/06Frames; Stringers; Longerons ; Fuselage sections
    • B64C1/12Construction or attachment of skin panels
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/01General aspects dealing with the joint area or with the area to be joined
    • B29C66/05Particular design of joint configurations
    • B29C66/10Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/11Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
    • B29C66/112Single lapped joints
    • B29C66/1122Single lap to lap joints, i.e. overlap joints
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/01General aspects dealing with the joint area or with the area to be joined
    • B29C66/05Particular design of joint configurations
    • B29C66/10Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/12Joint cross-sections combining only two joint-segments; Tongue and groove joints; Tenon and mortise joints; Stepped joint cross-sections
    • B29C66/128Stepped joint cross-sections
    • B29C66/1282Stepped joint cross-sections comprising at least one overlap joint-segment
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/01General aspects dealing with the joint area or with the area to be joined
    • B29C66/05Particular design of joint configurations
    • B29C66/10Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/12Joint cross-sections combining only two joint-segments; Tongue and groove joints; Tenon and mortise joints; Stepped joint cross-sections
    • B29C66/128Stepped joint cross-sections
    • B29C66/1286Stepped joint cross-sections comprising at least one bevelled joint-segment
    • B29C66/12861Stepped joint cross-sections comprising at least one bevelled joint-segment comprising at least two bevelled joint-segments
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/01General aspects dealing with the joint area or with the area to be joined
    • B29C66/05Particular design of joint configurations
    • B29C66/10Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/13Single flanged joints; Fin-type joints; Single hem joints; Edge joints; Interpenetrating fingered joints; Other specific particular designs of joint cross-sections not provided for in groups B29C66/11 - B29C66/12
    • B29C66/131Single flanged joints, i.e. one of the parts to be joined being rigid and flanged in the joint area
    • B29C66/1312Single flange to flange joints, the parts to be joined being rigid
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/01General aspects dealing with the joint area or with the area to be joined
    • B29C66/05Particular design of joint configurations
    • B29C66/20Particular design of joint configurations particular design of the joint lines, e.g. of the weld lines
    • B29C66/23Particular design of joint configurations particular design of the joint lines, e.g. of the weld lines said joint lines being multiple and parallel or being in the form of tessellations
    • B29C66/234Particular design of joint configurations particular design of the joint lines, e.g. of the weld lines said joint lines being multiple and parallel or being in the form of tessellations said joint lines being in the form of tessellations
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/40General aspects of joining substantially flat articles, e.g. plates, sheets or web-like materials; Making flat seams in tubular or hollow articles; Joining single elements to substantially flat surfaces
    • B29C66/47Joining single elements to sheets, plates or other substantially flat surfaces
    • B29C66/474Joining single elements to sheets, plates or other substantially flat surfaces said single elements being substantially non-flat
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/50General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/52Joining tubular articles, bars or profiled elements
    • B29C66/524Joining profiled elements
    • B29C66/5245Joining profiled elements for forming cross-shaped connections, e.g. for making window frames or X-shaped pieces
    • B29C66/52451Joining profiled elements for forming cross-shaped connections, e.g. for making window frames or X-shaped pieces with four right angles, e.g. for making +-shaped pieces
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/50General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/53Joining single elements to tubular articles, hollow articles or bars
    • B29C66/534Joining single elements to open ends of tubular or hollow articles or to the ends of bars
    • B29C66/5346Joining single elements to open ends of tubular or hollow articles or to the ends of bars said single elements being substantially flat
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/50General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/54Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles
    • B29C66/543Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles joining more than two hollow-preforms to form said hollow articles
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/70General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/72General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined
    • B29C66/721Fibre-reinforced materials
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29DPRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D99/00Subject matter not provided for in other groups of this subclass
    • B29D99/001Producing wall or panel-like structures, e.g. for hulls, fuselages, or buildings
    • B29D99/0014Producing wall or panel-like structures, e.g. for hulls, fuselages, or buildings provided with ridges or ribs, e.g. joined ribs
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/01General aspects dealing with the joint area or with the area to be joined
    • B29C66/05Particular design of joint configurations
    • B29C66/10Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/11Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
    • B29C66/112Single lapped joints
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/01General aspects dealing with the joint area or with the area to be joined
    • B29C66/05Particular design of joint configurations
    • B29C66/10Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/13Single flanged joints; Fin-type joints; Single hem joints; Edge joints; Interpenetrating fingered joints; Other specific particular designs of joint cross-sections not provided for in groups B29C66/11 - B29C66/12
    • B29C66/131Single flanged joints, i.e. one of the parts to be joined being rigid and flanged in the joint area
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/70General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/71General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the composition of the plastics material of the parts to be joined
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/70General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/72General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined
    • B29C66/721Fibre-reinforced materials
    • B29C66/7212Fibre-reinforced materials characterised by the composition of the fibres
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2105/00Condition, form or state of moulded material or of the material to be shaped
    • B29K2105/06Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29LINDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00Other particular articles
    • B29L2031/10Building elements, e.g. bricks, blocks, tiles, panels, posts, beams
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29LINDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00Other particular articles
    • B29L2031/30Vehicles, e.g. ships or aircraft, or body parts thereof
    • B29L2031/3076Aircrafts
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00Metal working
    • Y10T29/49Method of mechanical manufacture
    • Y10T29/49616Structural member making
    • Y10T29/49622Vehicular structural member making
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00Metal working
    • Y10T29/49Method of mechanical manufacture
    • Y10T29/49826Assembling or joining
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/24Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24058Structurally defined web or sheet [e.g., overall dimension, etc.] including grain, strips, or filamentary elements in respective layers or components in angular relation
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/24Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24132Structurally defined web or sheet [e.g., overall dimension, etc.] including grain, strips, or filamentary elements in different layers or components parallel

Definitions

  • the following disclosure relates generally to a monolithic integrated structures and, more particularly, to structures for use in aircrafts and other vehicles.
  • One well-known method for increasing aircraft performance is to reduce airframe weight through the use of state-of-the-art materials, such as composites, having relatively high strength-to-weight and stiffness-to-weight ratios.
  • Composite materials are generally described as being materials that include reinforcing fibers, such as graphite fibers, embedded in a polymeric matrix, such as an epoxy resin. Such materials will hereinafter be referenced as “fiber-reinforced composite” materials.
  • U.S. Pat. No. 4,310,132 discloses a built-up fuselage formed by skins in composite materials stiffened by integral stringers shaped with “J” section, crossed by metallic frames. The frames are cut in order to permit the passage of uninterrupted stringers through cut-outs. The stringers are attached to the frames using clips and mechanical fasteners.
  • U.S. Pat. No. 5,242,523 discloses a bonded fuselage, totally made of composite materials, with skins and stringers shaped with an “omega” cross-section, crossing the frames through cut-outs, wherein each stringer has pressure bridges provided by additional parts.
  • U.S. Pat. No. 7,134,629 discloses a built-up fuselage, totally made of composite materials, formed by integral skins stiffened by stringers shaped with an “omega” cross-section crossing the frames through cut-outs.
  • each of the frames can include a base portion and an upstanding portion projecting away from the base portion wherein the upstanding portion can include a plurality of openings (colloquially known as “mouse houses”) through which the continuous stringer passes.
  • Several problems can rise from the cut-outs, such as stress concentration, leading to small cracks which may grow in a straight line and extend through the complete section, spoiling the strength of the frame.
  • the present invention is therefore directed generally toward structural panels for use in manufacturing aircraft and other structures.
  • the present invention relates generally to a monolithic integrated structure including a skin, a stiffener and a frame without cut-outs and a method of manufacturing the said structure.
  • a monolithic structural panel formed entirely of a fiber-reinforced composite material will comprise a skin, and frame and stinger members attached to the skin, wherein intersections between the frame and stringer members include cross-plied laminae of fiber-reinforced composite material.
  • the frame and stringer members are substantially mutually orthogonal to one another.
  • the intersections between respective frame and stringer members comprise preformed modular units, wherein the modular units are structurally united to one another by lengthwise flanges formed of laminae of fiber-reinforced composite material.
  • Bridge elements (preferably generally V-shaped) may be provided at the intersections between the frame and stringer members, the bridge elements are joined to the stringer members by means of the lengthwise flanges.
  • a one-piece structural panel for aircraft may comprise mutually orthogonal frame and stringer members intersecting at a monolithic junction and formed entirely from a fiber-reinforced composite material.
  • methods of making a structural panel include joining frame and stringer members to a skin, wherein each of the skin and frame and stringer members is formed of a fiber-reinforced composite material, and wherein intersections between the frame and stringer members are formed by cross-plying laminae of fiber-reinforced composite material.
  • the frame and stringer members are mutually orthogonal to one another.
  • methods are provided to fabricate an aircraft structural panel by providing a preform of mutually orthogonal frame and stringer members formed of a fiber-reinforced composite material and having a monolithic junction therebetween, positioning the preform on a skin formed of a fiber-reinforced composite material, and thereafter co-curing the preform and the skin to form an aircraft structural panel.
  • FIG. 1 is a perspective view of one embodiment of a monolithic structural panel in accordance with the present invention
  • FIG. 2 is an enlarged cross-sectional elevational view of the monolithic structural panel depicted in FIG. 1 taken along line 2 - 2 therein;
  • FIG. 3 is an enlarged cross-sectional elevational view of the monolithic structural panel depicted in FIG. 1 taken along line 3 - 3 therein;
  • FIG. 4 is a schematic exploded view showing in greater detail one embodiment of the manner in which the junction of the stringer and frame members in the panel of FIG. 1 is constructed;
  • FIG. 5 is a perspective view showing the constructed junction of the stringer and frame members
  • FIG. 6 is a perspective view of another embodiment of a monolithic structural panel in accordance with the present invention.
  • FIG. 7 is a schematic exploded view showing in greater detail an embodiment of the manner in which the junction of the stringer and frame members in the panel of FIG. 6 is constructed;
  • the following disclosure describes monolithic integrated structure panel with bi-directional reinforcements having a I-shaped cross-sectional profile for use in manufacturing aircraft and other structures. Certain details are set forth in the following description and in the accompanying drawing FIGURES to provide a thorough understanding of various embodiments of the invention. It is important to note however that there are virtually no restrictions to the element profile and thus, in addition to the I-shaped cross-sectional profile exemplified, other cross-sectional profiles having C, Z, ⁇ and the like are possible. Other details describing well-known structures and systems often associated with aircraft structures and composite materials are not set forth in the following disclosure to avoid unnecessarily obscuring the description of the various embodiments of the invention.
  • FIGURES are merely illustrative of particular embodiments of the invention and obey engineering requirements and manufacturing characteristics particular to each design and application. Accordingly, other embodiments can have other details, dimensions, angles, and features without departing from the spirit or scope of the present invention. In addition, further embodiments can be practiced without several of the details described below.
  • monolithic is meant that the various structural components are integrated into a one-piece unit without readily discernible seams and without openings to accommodate intersecting structures. This is accomplished by means of the present invention by laminating plies of composite material one to another so as to structurally join by lamination preformed modular elements and/or to fabricate in situ the various components described herein (e.g., as described by U.S. Pat. No. 6,972,068, the entire content of which is expressly incorporated hereinto by reference).
  • FIGS. 1-3 An exemplary monolithic structural panel 10 according to one embodiment of the present invention is depicted in accompanying FIGS. 1-3 as including a skin 12 which is structurally reinforced by substantially mutually orthogonal frame and stringer members 14 , 16 , respectively.
  • Reinforcement members 18 , 20 form a reinforcement base adjacent the skin 12 for each of the frame and stringer members 14 , 16 , respectively.
  • the frame and stringer members 14 , 16 are each depicted as having a generally I-shaped cross-sectional profile. As noted previously, however, virtually any desired cross-sectional profile may be provided, Thus, in the exemplary embodiment depicted, the frame and stringer members 14 , 16 will have a web 14 - 1 , 16 - 1 joining the reinforcement members 18 , 20 and the upper flange caps 14 - 2 , 16 - 2 .
  • the frames 14 are provided with generally V-shaped bridge elements 22 which assist in monolithically joining the stringer members 16 to the frame members 14 at the orthogonal junction therebetween.
  • the intersection of the frame and stringer members 14 , 16 may be fabricated from preformed modular junction elements 24 a - 24 d .
  • the modular junction elements 24 a - 24 d are substantial mirror images of one another.
  • the bridge elements 22 may be formed from a pair of preformed bridge sections 22 a - 22 b that may be mirror-images relative to one another.
  • the continuous plies forming the reinforcement members 18 , 20 and the flange caps 16 - 2 and 14 - 2 are cross-laminated with one another and with the modular junction elements 24 a - 24 d , 22 a and 22 b so as to form, after cure, a monolithic rigid intersection between the frame and stringer members 14 , 16 , respectively as depicted in accompanying FIG. 5 .
  • the skin 12 , the frame members 14 and the stringer members 16 are preferably formed from composite materials, such as carbon fiber reinforced epoxy laminates.
  • the frame members 14 and/or stringer members 16 can be co-cured or co-bonded or bonded to the skin 12 .
  • the frames members 14 and/or stringer members 16 can be joined to the skin 12 during a co-curing process in which the frame members and/or stringer members 16 are co-cured with the skin 12 at an elevated temperature and pressure.
  • a plurality of stiffener preforms comprising stringer members 16 and frame members 14 may be laid across the skin 12 on top of pre-positioned layers or strips of an adhesive or bonding substance (e.g., joining elements) that, upon curing of the panel, fixedly bonds the frame members 14 and stringer members 16 to the panel (i.e., so that the lower flanges of frame members 14 and stringer members 16 are joined to the skins forming the reinforcement members 18 , 20 , respectively).
  • an adhesive or bonding substance e.g., joining elements
  • Frame members 14 and stringer members 16 of each module attach one to another, at three different regions, namely the outer flanges (reinforcement members 18 , 20 ), the webs 14 - 1 , 16 - 1 , and the inner flanges 14 - 2 . 16 - 2 .
  • flanges i.e., flanges 14 - 2 , 16 - 2 and the reinforcement members 18 , 20
  • webs 14 - 1 , 16 - 1 are stacks of laminae, i.e. plies of laminated composite material.
  • Some laminae of the inner flanges 14 - 2 of the frame members 14 are placed one on top of the other in an alternate way in order to match the inner flanges 16 - 2 of the stringer members 16 , forming an overlapped local joint.
  • the outer flanges (reinforcement members 18 , 20 ) of both frame members 14 and stringer members 16 are laminated with the skins 12 along their entire lengthwise extent.
  • the webs 14 - 1 of the frame members 14 and/or the webs 16 - 1 of the stringer members 16 are interrupted and spliced at the crossing points, with or without additional plies.
  • the frames 14 do not need to have openings at the locations so as to allow the stringer members 16 to pass therethrough as is the case with conventional constructions.
  • FIGS. 6 and 7 An alternative embodiment of a monolithic structural panel 30 is depicted in accompanying FIGS. 6 and 7 .
  • the panel 30 shown in FIG. 6 is comprised of a skin 32 and mutually orthogonal frame and stringer members 34 , 36 , respectively.
  • Reinforcement members 38 , 40 form a reinforcement base adjacent the skin 32 for each of the frame and stringer members 34 , 36 , respectively.
  • the frame and stringer members 34 , 36 will have a web 34 - 1 , 36 - 1 joining the reinforcement members 38 , 40 and the upper flange caps 34 - 2 , 36 - 2 .
  • These upper flange caps 34 - 2 , 36 - 2 will be formed of cross-laminated plies of composite material so that when cured a monolithic upper flange is created. After curing, the junctions between the monolithic upper flange caps 34 - 2 , 36 - 2 may be beveled somewhat by a suitable grinding tool so as to provide stress relief at the junction.
  • the juncture of the frame and stringer members 34 , 36 may be fabricated from preformed modular junction elements 42 a - 42 d as shown in accompanying FIG. 7 .
  • the continuous plies forming the reinforcement members 38 , 40 and the flange caps 36 - 2 and 34 - 2 are cross-laminated with one another and with the modular junction elements 42 a - 42 d so as to form, after cure, a monolithic rigid junction between the frame and stringer members 34 , 36 .

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Moulding By Coating Moulds (AREA)

Abstract

Structural panels for use in manufacturing fuselage bodies and other aircraft structures are disclosed herein. In one embodiment, a monolithic integrated structural panel is configured to include a skin, an array of stiffeners and an array of frames which are preferably arranged in a mutually orthogonal layout, without the need of cut-outs in any of the crossing elements. One advantage of the disclosed embodiments is that the frame and stringer members have continuous flanges and spliced webs. The disclosed embodiments herein are compatible with composite materials technology, offering another advantage, namely the possibility of manufacturing integrated products in a single cure (“one-shot”) cycle. A structure of composite materials, e.g. carbon fiber reinforced plastics, typically comprises a skin panel, reinforced by frame and stringer members. A monolithic integrated structure constructed in accordance with the disclosed embodiments is well-suited for use as a portion of an aircraft structure, for example an aircraft fuselage, wing or empennage.

Description

    FIELD OF THE INVENTION
  • The following disclosure relates generally to a monolithic integrated structures and, more particularly, to structures for use in aircrafts and other vehicles.
  • BACKGROUND AND SUMMARY OF THE INVENTION
  • Aircraft manufacturers continuously attempt to improve aircraft performance by reducing both weight and manufacturing costs while maintaining or improving structural strength. One well-known method for increasing aircraft performance is to reduce airframe weight through the use of state-of-the-art materials, such as composites, having relatively high strength-to-weight and stiffness-to-weight ratios. Composite materials are generally described as being materials that include reinforcing fibers, such as graphite fibers, embedded in a polymeric matrix, such as an epoxy resin. Such materials will hereinafter be referenced as “fiber-reinforced composite” materials.
  • A variety of composite designs are being proposed on an on-going basis by a number of aircraft manufacturers.
  • U.S. Pat. No. 4,310,132 discloses a built-up fuselage formed by skins in composite materials stiffened by integral stringers shaped with “J” section, crossed by metallic frames. The frames are cut in order to permit the passage of uninterrupted stringers through cut-outs. The stringers are attached to the frames using clips and mechanical fasteners.
  • U.S. Pat. No. 5,242,523 discloses a bonded fuselage, totally made of composite materials, with skins and stringers shaped with an “omega” cross-section, crossing the frames through cut-outs, wherein each stringer has pressure bridges provided by additional parts.
  • U.S. Pat. No. 7,134,629 discloses a built-up fuselage, totally made of composite materials, formed by integral skins stiffened by stringers shaped with an “omega” cross-section crossing the frames through cut-outs.
  • Considerable disadvantages exist however in the known prior art, which requires the installation of the stringers and frames. Manufacturing stringers with different geometries is very expensive. Another disadvantage is that some stringer installation by riveting is time-consuming and cost-demanding. Such a method creates a great number of holes through the outer skin, which always increases the potential for corrosion and fatigue problems. Another concern is the intersection where the stringer passes the frames. Specifically, according to the current state of the art, each of the frames can include a base portion and an upstanding portion projecting away from the base portion wherein the upstanding portion can include a plurality of openings (colloquially known as “mouse houses”) through which the continuous stringer passes. Several problems can rise from the cut-outs, such as stress concentration, leading to small cracks which may grow in a straight line and extend through the complete section, spoiling the strength of the frame.
  • As conventional methods for manufacturing airframes in composite materials often require expensive tooling and labor-intensive assembly procedures it would therefore be highly desirable to develop new panel structures with reduced weight and increased cost efficiency in the manufacturing process. It is towards fulfilling such needs that the present invention is directed.
  • The present invention is therefore directed generally toward structural panels for use in manufacturing aircraft and other structures. The present invention relates generally to a monolithic integrated structure including a skin, a stiffener and a frame without cut-outs and a method of manufacturing the said structure.
  • According to some embodiments, a monolithic structural panel formed entirely of a fiber-reinforced composite material will comprise a skin, and frame and stinger members attached to the skin, wherein intersections between the frame and stringer members include cross-plied laminae of fiber-reinforced composite material. In some embodiments, the frame and stringer members are substantially mutually orthogonal to one another. The intersections between respective frame and stringer members comprise preformed modular units, wherein the modular units are structurally united to one another by lengthwise flanges formed of laminae of fiber-reinforced composite material. Bridge elements (preferably generally V-shaped) may be provided at the intersections between the frame and stringer members, the bridge elements are joined to the stringer members by means of the lengthwise flanges.
  • A one-piece structural panel for aircraft according to other embodiments of the invention may comprise mutually orthogonal frame and stringer members intersecting at a monolithic junction and formed entirely from a fiber-reinforced composite material.
  • In other embodiments, methods of making a structural panel are provided which include joining frame and stringer members to a skin, wherein each of the skin and frame and stringer members is formed of a fiber-reinforced composite material, and wherein intersections between the frame and stringer members are formed by cross-plying laminae of fiber-reinforced composite material. In some preferred embodiments, the frame and stringer members are mutually orthogonal to one another.
  • In certain embodiments, methods are provided to fabricate an aircraft structural panel by providing a preform of mutually orthogonal frame and stringer members formed of a fiber-reinforced composite material and having a monolithic junction therebetween, positioning the preform on a skin formed of a fiber-reinforced composite material, and thereafter co-curing the preform and the skin to form an aircraft structural panel.
  • These and other aspects and advantages will become more apparent after careful consideration is given to the following detailed description of the preferred exemplary embodiments thereof.
  • BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
  • Reference will hereinafter be made to the accompanying drawings, wherein like reference numerals throughout the various FIGURES denote like structural elements, and wherein;
  • FIG. 1 is a perspective view of one embodiment of a monolithic structural panel in accordance with the present invention;
  • FIG. 2 is an enlarged cross-sectional elevational view of the monolithic structural panel depicted in FIG. 1 taken along line 2-2 therein;
  • FIG. 3 is an enlarged cross-sectional elevational view of the monolithic structural panel depicted in FIG. 1 taken along line 3-3 therein;
  • FIG. 4 is a schematic exploded view showing in greater detail one embodiment of the manner in which the junction of the stringer and frame members in the panel of FIG. 1 is constructed;
  • FIG. 5 is a perspective view showing the constructed junction of the stringer and frame members;
  • FIG. 6 is a perspective view of another embodiment of a monolithic structural panel in accordance with the present invention; and
  • FIG. 7 is a schematic exploded view showing in greater detail an embodiment of the manner in which the junction of the stringer and frame members in the panel of FIG. 6 is constructed;
  • DETAILED DESCRIPTION OF THE INVENTION
  • The following disclosure describes monolithic integrated structure panel with bi-directional reinforcements having a I-shaped cross-sectional profile for use in manufacturing aircraft and other structures. Certain details are set forth in the following description and in the accompanying drawing FIGURES to provide a thorough understanding of various embodiments of the invention. It is important to note however that there are virtually no restrictions to the element profile and thus, in addition to the I-shaped cross-sectional profile exemplified, other cross-sectional profiles having C, Z, Ω and the like are possible. Other details describing well-known structures and systems often associated with aircraft structures and composite materials are not set forth in the following disclosure to avoid unnecessarily obscuring the description of the various embodiments of the invention.
  • Many of the details, dimensions, angles, and other features shown in the accompanying drawing FIGURES are merely illustrative of particular embodiments of the invention and obey engineering requirements and manufacturing characteristics particular to each design and application. Accordingly, other embodiments can have other details, dimensions, angles, and features without departing from the spirit or scope of the present invention. In addition, further embodiments can be practiced without several of the details described below.
  • By the term “monolithic” is meant that the various structural components are integrated into a one-piece unit without readily discernible seams and without openings to accommodate intersecting structures. This is accomplished by means of the present invention by laminating plies of composite material one to another so as to structurally join by lamination preformed modular elements and/or to fabricate in situ the various components described herein (e.g., as described by U.S. Pat. No. 6,972,068, the entire content of which is expressly incorporated hereinto by reference).
  • An exemplary monolithic structural panel 10 according to one embodiment of the present invention is depicted in accompanying FIGS. 1-3 as including a skin 12 which is structurally reinforced by substantially mutually orthogonal frame and stringer members 14, 16, respectively. Reinforcement members 18, 20 form a reinforcement base adjacent the skin 12 for each of the frame and stringer members 14, 16, respectively.
  • The frame and stringer members 14, 16 are each depicted as having a generally I-shaped cross-sectional profile. As noted previously, however, virtually any desired cross-sectional profile may be provided, Thus, in the exemplary embodiment depicted, the frame and stringer members 14, 16 will have a web 14-1, 16-1 joining the reinforcement members 18, 20 and the upper flange caps 14-2, 16-2.
  • The frames 14 are provided with generally V-shaped bridge elements 22 which assist in monolithically joining the stringer members 16 to the frame members 14 at the orthogonal junction therebetween.
  • As is perhaps better shown in accompanying FIG. 4, the intersection of the frame and stringer members 14, 16 may be fabricated from preformed modular junction elements 24 a-24 d. In the embodiment depicted, the modular junction elements 24 a-24 d are substantial mirror images of one another. Similarly, the bridge elements 22 may be formed from a pair of preformed bridge sections 22 a-22 b that may be mirror-images relative to one another. The continuous plies forming the reinforcement members 18, 20 and the flange caps 16-2 and 14-2 (the latter being represented by bridge sections 14-2 a and 14-2 b so as to join the bridge sections 22 a, 22 b one to another and to the other components) are cross-laminated with one another and with the modular junction elements 24 a-24 d, 22 a and 22 b so as to form, after cure, a monolithic rigid intersection between the frame and stringer members 14, 16, respectively as depicted in accompanying FIG. 5.
  • The skin 12, the frame members 14 and the stringer members 16 are preferably formed from composite materials, such as carbon fiber reinforced epoxy laminates. The frame members 14 and/or stringer members 16 can be co-cured or co-bonded or bonded to the skin 12. For example, in one embodiment, the frames members 14 and/or stringer members 16 can be joined to the skin 12 during a co-curing process in which the frame members and/or stringer members 16 are co-cured with the skin 12 at an elevated temperature and pressure.
  • A plurality of stiffener preforms comprising stringer members 16 and frame members 14 (the latter crosswise to the stringer members 16) may be laid across the skin 12 on top of pre-positioned layers or strips of an adhesive or bonding substance (e.g., joining elements) that, upon curing of the panel, fixedly bonds the frame members 14 and stringer members 16 to the panel (i.e., so that the lower flanges of frame members 14 and stringer members 16 are joined to the skins forming the reinforcement members 18, 20, respectively).
  • Frame members 14 and stringer members 16 of each module attach one to another, at three different regions, namely the outer flanges (reinforcement members 18, 20), the webs 14-1, 16-1, and the inner flanges 14-2. 16-2. In frame members 14 and stringer members 16, flanges (i.e., flanges 14-2, 16-2 and the reinforcement members 18, 20) and webs 14-1, 16-1 are stacks of laminae, i.e. plies of laminated composite material. Some laminae of the inner flanges 14-2 of the frame members 14 are placed one on top of the other in an alternate way in order to match the inner flanges 16-2 of the stringer members 16, forming an overlapped local joint. The outer flanges (reinforcement members 18, 20) of both frame members 14 and stringer members 16 are laminated with the skins 12 along their entire lengthwise extent. The webs 14-1 of the frame members 14 and/or the webs 16-1 of the stringer members 16 are interrupted and spliced at the crossing points, with or without additional plies.
  • Longitudinal and transversal plies are continuous, generating an overlapped area in each intersection. Type, direction and number of plies are laid-out according to engineering requirements. At every intersection, the web of one element can be folded to match the web of the orthogonal element, in a splicing region. Therefore, according to preferred embodiments of the present invention, the frames 14 do not need to have openings at the locations so as to allow the stringer members 16 to pass therethrough as is the case with conventional constructions.
  • An alternative embodiment of a monolithic structural panel 30 is depicted in accompanying FIGS. 6 and 7. In this regard, similar to the panel 10 described above, the panel 30 shown in FIG. 6 is comprised of a skin 32 and mutually orthogonal frame and stringer members 34, 36, respectively. Reinforcement members 38, 40 form a reinforcement base adjacent the skin 32 for each of the frame and stringer members 34, 36, respectively. The frame and stringer members 34, 36 will have a web 34-1, 36-1 joining the reinforcement members 38, 40 and the upper flange caps 34-2, 36-2. These upper flange caps 34-2, 36-2 will be formed of cross-laminated plies of composite material so that when cured a monolithic upper flange is created. After curing, the junctions between the monolithic upper flange caps 34-2, 36-2 may be beveled somewhat by a suitable grinding tool so as to provide stress relief at the junction.
  • Thus, as was the case with panel 10 described previously, the juncture of the frame and stringer members 34, 36 may be fabricated from preformed modular junction elements 42 a-42 d as shown in accompanying FIG. 7. The continuous plies forming the reinforcement members 38, 40 and the flange caps 36-2 and 34-2 are cross-laminated with one another and with the modular junction elements 42 a-42 d so as to form, after cure, a monolithic rigid junction between the frame and stringer members 34, 36.
  • While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims (14)

1. A monolithic structural panel comprising:
a skin, and
frame and stinger members attached to the skin, wherein each of the frame members, stringer members and skin is formed of a fiber-reinforced composite material, and wherein
intersections between the frame and stringer members include cross-plied laminae of fiber-reinforced composite material.
2. A panel as in claim 1, wherein the intersections between the frame and stringer members comprise preformed modular units, and wherein the modular units are structurally united to one another by lengthwise flanges formed of laminae of fiber-reinforced composite material.
3. A panel as in claim 2, wherein the frame members include bridge elements at the intersections between the frame and stringer members, the bridge elements are joined to the stringer members by means of the lengthwise flanges.
4. A panel as in claim 3, wherein the bridge elements are generally V-shaped.
5. A one-piece structural panel for aircraft comprising frame members and stringer members intersecting at respective monolithic junctions and formed entirely from a fiber-reinforced composite material.
6. A panel as in claim 5, further comprising a skin formed from a fiber-reinforced composite material joined to the frame and stringer members.
7. A panel as in claim 5, wherein the intersections between the frame and stringer members comprise preformed modular units, and wherein the modular units are structurally united to one another by lengthwise flanges formed of laminae of fiber-reinforced composite material.
8. A panel as in claim 7, wherein the frame members include bridge elements at the intersections between the frame and stringer members, the bridge elements are joined to the stringer members by means of the lengthwise flanges.
9. A panel as in claim 8, wherein the bridge elements are generally V-shaped.
10. A method of making a structural panel comprising joining substantially mutually orthogonal frame and stinger members to a skin, wherein each of the skin and frame and stringer members is formed of a fiber-reinforced composite material, and wherein intersections between the frame and stringer members are formed by cross-plying laminae of fiber-reinforced composite material.
11. A method as in claim 10, which comprises providing preformed modular units formed of a fiber-reinforced composite material of the intersection between the frame and stringer members, and structurally uniting the modular units one to another by lengthwise flanges formed of laminae of fiber-reinforced composite material.
12. A method as in claim 11, further comprising providing bridge elements at the intersections between the frame and stringer members, and joining the bridge elements to the stringer members by means of the lengthwise flanges.
13. A method as in claim 12, wherein the bridge elements are generally V-shaped.
14. A method of fabricating an aircraft structural panel comprising:
providing a preform of frame members and stringer members each formed of a fiber-reinforced composite material and having respective monolithic junctions therebetween;
positioning the preform on a skin formed of a fiber-reinforced composite material; and thereafter
co-curing the preform and the skin to form an aircraft structural panel.
US12/165,213 2008-06-30 2008-06-30 Monolithic integrated structural panels especially useful for aircraft structures Expired - Fee Related US8079549B2 (en)

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BRPI0822480A BRPI0822480B1 (en) 2008-06-30 2008-12-05 monolithic integrated structural panels especially useful for aircraft structures and methods for producing the same
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